hesitation under load upon acceleration

[bob hall]

All of a sudden my SL is missing, hesitating, balking when accelerating away from a stop, warm or cold.  As soon as the vehicle has any speed it smoothes out & runs fine. Background; 1965 230SL new 280 engine etc, etc.  The car lives at 7000 ft.
This issue has probably been addressed somewhere in the forum but I can't find such.  I would appreciate some advise.
Bob Hall

[Shvegel]

If it is a hard staccato miss it is most certainly ignition related as a fuel miss will usually feel like you are pressing and releasing the gas pedal. If the car still has points I would start there. I have a pertronix ignitor which replace the points with an electronic setup that I love.  besides that all the standard stuff. Plugs,wires,cap rotor.

Also if the plugs are Champion Resistor get them out of there. Plugs should not be resistor and Champions have a tendency to have the resistance increase dramatically which raises the firing voltage to the point that the spark tries to find an easier way to ground than across the gap of the spark plug.

[ja17]

Hello,

Good advice by Shvegel. Check the inexpensive items first. Possibly your ingintion contacts are closing up. Check the dwell or gap.

[bob hall]

Thanks, will start there & see where it all leads

[mdsalemi]

Once you rule out ignition, don't forget the Blacklick CO test for rich/lean.  MIne hesitated too, but it was fuel--ever so slightly on the lean side.

[m300cab]

also check for arcing from old wires at and around the coil

[mdsalemi]

also check for arcing from old wires at and around the coil

...good point.  Dirty wires, too, will arc or bleed on the outside.  Sometimes one bad wire, which could mean the connection at either end, can ruin your day. (Had that happen on a 1989 Ford Sierra /Merkur XR4Ti)

[graphic66]

I just found a bad coil wire that was causing issues. It had the "wood screw" connector on one end. The wood screw had the end burned off and was arcing from the wire to the tip of the screw. Just that little space caused a problem. Also, you can check each spark plug wire with an ohm meter. you should have ideally 1000 ohms. I found out that my Beru wires had 1000 ohm resistance on the spark plug boot and another 1000 ohms on the end that goes into the dizzy. I am in the process of making a set of wires as there are none available that are correct for the 230SL with the wires in a tube along the valve cover unless you want the very unoriginal looking  90 deg. metal connector on the number one cyl. with the others straight and black rubber. The Beru brand ones that K&K sells won't fit as I believe these are just for the newer style loom wiring.

[ja17]

Hello,
Some later original wire sets used the 5,000 ohm resistor ends at the spark plugs (later factory electronic ignition cars equiped with radios).  During replacement most owners are going to the 1,000 ohm ends, since resistor plugs have an additional 5,000 ohm resistance. Original non-resistor spark  plugs had virtually no resistance.